This invention relates to an apparatus for refining paper materials which is particularly adapted to remove heavy and light foreign substances and printing ink which are admixed with a starting material to be treated and thereafter to refine only the paper material through screen means.
The Japanese Patent Publication No. 59-34838 of the same applicant discloses a paper material refining apparatus which operates to remove heavy and light foreign substances from the starting material to be treated and, thereafter, to refine the paper material by removing the foreign substances through a screen plate. The refining apparatus is provided with a primary and secondary chambers of thin type separated by the interposed screen plate and an impeller disposed in the primary chamber near the screen plate. A port for feeding the paper material is disposed in the front wall of the primary chamber at a position corresponding to the central portion of the impeller. A light foreign substance collector is installed within the feeding port in coaxial alignment therewith, and the collector is connected to a separator through piping. A discharging port for the heavy foreign substance is provided at the outer periphery of the primary chamber in a tangential state thereto, and the discharging port is also connected to the separator through piping.
According to the refining apparatus disclosed in the Japanese Patent Publication referred to hereinabove, the heavy foreign substances admixed in the starting material to be treated are moved from the central portion of the primary chamber toward the outer periphery thereof along the front wall by the action of the centrifugal force due to the swirling motion of the impeller, collected there, and then discharged outwardly through the discharging port. The light foreign substance is collected, because the center of the swirling flow is pressure-reduced, at this pressure reduced portion, i.e., at a portion in front of the collector in the form of a bell, flows inside the collector while swirling, and then is outwardly discharged. Accordingly, only the paper material, with the heavy and light substances removed remains near the location of the impeller in the primary chamber, and the paper material can be effectively refined through the screen plate without clogging thereof by the pressure difference between the primary chamber and the secondary chamber caused by the rotation of the impeller.
However, the refining apparatus of the described prior type is not provided with any means for removing printing ink material, simply called ink hereinafter, so that when a waste paper material printed with the ink is used as a starting material to be refined, the paper material refined and discharged may include the ink. Thus this prior refining apparatus requires additional means for removing the ink after the refining process and the provision of such additional means involves much cost and time.